Problem: Evaluate $8a-1+0.5b$ when $a=\dfrac14$ and $b=10$.
Answer: Let's substitute $ a= {\dfrac14}$ and $ b={10}$ into the expression. $\phantom{=}8{ {a}} -1+0.5{b}$ $=8\left(\dfrac{{1}}{4}\right)-1+0.5 ({10})$ $=2-1+5$ $=6$